Cavity Cooling a Single Charged Levitated Nanosphere

Abstract

Optomechanical cavity cooling of levitated objects offers the possibility for laboratory investigation of the macroscopic quantum behavior of systems that are largely decoupled from their environment. However, experimental progress has been hindered by particle loss mechanisms, which have prevented levitation and cavity cooling in a vacuum. We overcome this problem with a new type of hybrid electro-optical trap formed from a Paul trap within a single-mode optical cavity. We demonstrate a factor of 100 cavity cooling of 400 nm diameter silica spheres trapped in vacuum. This paves the way for ground-state cooling in a smaller, higher finesse cavity, as we show that a novel feature of the hybrid trap is that the optomechanical cooling becomes actively driven by the Paul trap, even for singly charged nanospheres.

Nonlinear Dynamics and Strong Cavity Cooling of Levitated Nanoparticles

“…We stress that these nonlinear dynamical effects are unrelated to variations in mechanical oscillation frequency arising when the particle samples anharmonicities in the potential [17], although we note these are also observable in our data. as compared to our previous work [16], which exposes the G 2 coupling, there is greatly enhanced (linear) optomechanical cavity cooling. This enables us to show for the first time permanent and stable optical cavity trapping of a levitated nanoparticle at pressures limited by our current equipment ∼ 10 −6 mbar, where we infer millikelvin temperatures.…”

“…Finally we identify a previously unobserved shift of the Paul trap secular frequencies due to the optical cavity, which we show gives valuable information on the system, such as the nanoparticle charge and mean number of photons in the cavity. The optomechanical cooling of levitated nanoparticles to the quantum regime has been the subject of several recent theoretical [18][19][20][21][22] and experimental [16,[23][24][25][26] studies, due to their isolation from environmental decoherence. While there has been success cooling nanoparticles with active feedback [23,24], passive cavity cooling has been hindered by particle loss processes which prevented optical trapping below a few mBar [22,26,27].…”

“…Not only can G 1 allow unwanted back-action, but a large G 2 1 contribution (e.g. [14]) can mask the signatures of true nonlinear G 2 coupling.In this work, we study a nanosphere levitated in a hybrid system formed from a Paul trap and an optical cavity [16] as shown in fig 1. The output of the cavity is used to access the linear and nonlinear dynamics of the particle. We are able to tune the G 1 : G 2 ratio to reach G 2 G 1 , isolating the true nonlinear dynamics.…”

Control of Fano resonances and slow light using Bose-Einstein condensates in a nanocavity

“…Due to the ubiquitous nature of the mechanical motion, such resonators couple with many kinds of quantum devices, that range from atomic systems to the solid-state electronic circuits [33][34][35][36]. More recently, a new development has been made in the field of levitated optomechanics [37][38][39], in which the mechanical oscillator is supported only by the light field. These platforms offer the possibility of a generation of highly-sensitive sensors, which are able to detect (for example) weak forces, with a precision limited only by quantum uncertainties [39].…”

“…More recently, a new development has been made in the field of levitated optomechanics [37][38][39], in which the mechanical oscillator is supported only by the light field. These platforms offer the possibility of a generation of highly-sensitive sensors, which are able to detect (for example) weak forces, with a precision limited only by quantum uncertainties [39]. Fano resonances [40,41], optomechanically induced transparency [42] with single [43] and multiple windows [41,44,45], superluminal and subluminal effects [46][47][48][49][50][51][52][53][54][55][56][57][58][59] have also been observed in optomechanical systems, where nano dimensions and normal environmental conditions have paved the new avenues towards stateof-the-art potential applications, such as imaging and cloaking, telecommunication, interferometry, quantumoptomechanical memory and classical signal processing applications [60][61][62][63].…”